LONG-TERM DEBT (Tables)

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Schedule of Long-term Debt

			2011								2010
					NVE								NVE
Long-Term Debt:			Consolidated		Holding Co.		NPC		SPPC		Consolidated		Holding Co.		NPC		SPPC
Secured Debt
	General and Refunding Mortgage
	Securities
		8.25% NPC Series A due 2011	$	0	$	0	$	0	$	0	$	350,000	$	0	$	350,000	$	0
		6.50% NPC Series I due 2012		130,000		0		130,000		0		130,000		0		130,000		0
		5.875% NPC Series L due 2015		250,000		0		250,000		0		250,000		0		250,000		0
		5.95% NPC Series M due 2016		210,000		0		210,000		0		210,000		0		210,000		0
		6.65% NPC Series N due 2036		370,000		0		370,000		0		370,000		0		370,000		0
		6.50% NPC Series O due 2018		325,000		0		325,000		0		325,000		0		325,000		0
		6.75% NPC Series R due 2037		350,000		0		350,000		0		350,000		0		350,000		0
		6.50% NPC Series S due 2018		500,000		0		500,000		0		500,000		0		500,000		0
		7.375% NPC Series U due 2014		125,000		0		125,000		0		125,000		0		125,000		0
		7.125% NPC Series V due 2019		500,000		0		500,000		0		500,000		0		500,000		0
		5.375% NPC Series X due 2040		250,000		0		250,000		0		250,000		0		250,000		0
		5.45% NPC Series Y due 2041		250,000		0		250,000		0		0		0		0		0
		6.00% SPPC Series M due 2016		450,000		0		0		450,000		450,000		0		0		450,000
		6.75% SPPC Series P due 2037		251,742		0		0		251,742		251,742		0		0		251,742
		5.45% SPPC Series Q due 2013		250,000		0		0		250,000		250,000		0		0		250,000
	Variable Rate Debt (Secured by
		General and Refunding Mortgage
		Securities)
		NPC IDRB Series 2000A due 2020		98,100		0		98,100		0		98,100		0		98,100		0
		NPC PCRB Series 2006 due 2036		37,700		0		37,700		0		37,700		0		37,700		0
		NPC PCRB Series 2006A due 2032		37,975		0		37,975		0		37,975		0		37,975		0
		SPPC PCRB Series 2006A due 2031		58,200		0		0		58,200		58,200		0		0		58,200
		SPPC PCRB Series 2006B due 2036		75,000		0		0		75,000		75,000		0		0		75,000
		SPPC PCRB Series 2006C due 2036		81,475		0		0		81,475		81,475		0		0		81,475
		Revolving Credit Facilities		0		0		0		0		15,000		0		0		15,000
Senior Notes
		6.75% NVE Senior Notes due 2017		0		0		0		0		191,500		191,500		0		0
		6.25% NVE Senior Notes due 2020		315,000		315,000		0		0		315,000		315,000		0		0
		2.81% NVE Term Loan due 2014		195,000		195,000		0		0		0		0		0		0
Obligations under capital leases				51,270		0		51,270		0		55,735		0		55,735		0
Unamortized bond premium
and discount, net				(12,546)		0		(25,455)		12,909		2,611		1		(11,748)		14,358
Current maturities				(139,985)		0		(139,985)		0		(355,929)		0		(355,929)		0
Total Long-Term Debt			$	5,008,931	$	510,000	$	3,319,605	$	1,179,326	$	4,924,109	$	506,501	$	3,221,833	$	1,195,775

Schedule of Maturities of Long-term Debt [Table Text Block]

	NVE		NVE
	Consolidated		Holding Co.		NPC		SPPC
2012(1)	$	134,822	$	-	$	134,822	$	-
2013		255,405		-		5,405		250,000
2014		323,513		195,000		128,513		-
2015		251,039		-		251,039		-
2016		211,245		-		211,245		-
		1,176,024		195,000		731,024		250,000
Thereafter		3,985,438		315,000		2,754,021		916,417
		5,161,462		510,000		3,485,045		1,166,417
Unamortized Premium (Discount) Amount		(12,546)		-		(25,455)		12,909
Total Debt	$	5,148,916	$	510,000	$	3,459,590	$	1,179,326

Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]

2012		$	9,828
2013			9,845
2014			7,435
2015			4,831
2016			4,918
Thereafter			61,112
	Total minimum lease payments	$	97,969
	Less amounts representing interest	$	(46,699)
Present value of net minimum lease payments		$	51,270